Flush latch assembly



July 19, 1949. IT. HIIBECK ET AL FLUSH LATCH ASSEMBLY Filed April 16, 1945 Patented July 19, 1949 FLUSH LATCH AS SEMBLY Theodorel lerbert Beck, Los Angeles, and Leslie 1 Philip Glick, Hollywood, 'Calif., assign'ors, by nicsne assignments, to Clark Hartwell and Eleanor M. Hartwell, copartners, doing business as Hartwell Aviation SupplyCompany, Los An- .geles, Calif.

Application April 16, 1945, serial No. 588,436

'Claims. 1

Our invention relates to latch assemblies, more particularly to flush type latch assemblies adapted to be installed in the exterior surfaces of aircraft which must be free of projections or indentations.

Among the objects of our invention are:

First, to provide a latch assembly which is particularly designed for the flush mounting of inspection panels, access doors or the like, in the skin of an aircraft.

Second, to provide afflush'type latch assembly which maybe constructed without introducing appreciable problems of weight from heavier or stronger material than the structure in which it is mounted, or the panel which it supports, and is particularly designed so that'it provides in itself, its own stop or limit means. Thus the loads incidental to latching and unlatc'hing the assembly, are carried by the assemblyitself inead of the surrounding structure.

Third, to provide a flush-type latch assembly which may be employed in sets'to provide the entire interlocking connection between a panel and surroundin structure so that the panel may be bodily removed or the latch assembly may be employed in association withhinge means, if it is desired to so mount the panel.

Fourth, to provide alatch assembly which-ah iords a positive lock unaffected by inertia'loads in any direction, or by forces due to the slip stream or otherwise subject to accidental release, but which may be readily and quickly opened when desired'without the aid of tools.

With the above and other objects in view as may appear hereinafter, reference' is' directed to the accompanying drawings in' which:

Fig. 1 is an exterior'view of our latch assembly.

Fig. 2 is an enlarged interior view of our latch assembly.

Fig. 3 is an enlarged side elevational' view of the latch assembly.

Fig. 4 is an enlarged longitudinal sectional view thereof taken through 4-4 oi'Fig. 2.

The latch assembly includes a mounting plate 3 formed of sheet material. The mountingplate is divided to form twoside flanges 2 by means of a longitudinal slot extending-the length of the mounting plate except for a narrow -web t at one end.

A portion of the material removed =-to form the slot, is bent at right angles to the side flanges 2 to form an inwardly extending pair ofnlatch lever bearings earsor lugs 4:-and: similar keeper lever bearing ears orlugs ii. Thelatch lever ears are disposed=adjacent 'the end oi the'l plate 2 remote from the Web 3, and arcconnected by a latch lever journal pin 6 which journals .a latch lever i intermediateits ends.

The latch lever is formed oi sheet material and is channel shape in-cross-section. The latch lever includes an arm B'thesurface of which is offset inwardly from then'ormal surface of the lever so as to underlie the margins A of anopening as indicated in Fig. "4.

The-other arm 9 of the latch leverlis fiush, that is, it is intended to occupy a position whenclosed, flush with the surface of the panel on which the latch assembly is mounted as well-as-the surrounding structure. The extende'dend of the arms is provided with an inwardly offset lip 10. The extremity of the :arm is doubled backward inform a cam face I l extending in angular relation' with theouter surfaceot the arm. Theside walls of the channel shape latchlever l may taper at'their extremities to form marginal supports for thecam face i l.

The bearing lugs 5 are connected by ajournal pin H! which journals a keeper'lever 13. The keeper lever [B is likewise channel shape in crosssection but preferably substantiallywider'than the latch lever. The face of'the cross portion of thechannel shape keeper lever when in its closed position, flush with the arm 0 of the latch lever. The end of the keeper lever adjacentzthe latch lever is cut back from its side walls and its "edge portion'iorms withthe journal-pin l2 a slot which receives the oifset tipill and cam face II of the latch lever'l, as shown best in Fig. 4.

The extended end of-the keeper lever 13 is offset as indicated by M, to-flt under and bear against the web 3' when the keeper lever is in its closed position.

The side walls of the keeper lever'are directed forwardly of'the-journal pin l2, forming 1extensions [5 to which are attached the extremities of a pair ofsprings [6. The remainingends of the springs l6 are joined to inwardly directed extensions l'l'iormed by the side walls or the latch lever l. The relative positions of the connections between thesprings l6 and the extensions IS-and I! with respect to thejournal pins-6 and 12, are such that the force exerted by the springs, tends to rotate the latch lever into right angular position with the mounting. plate I, with its arm 9 projecting outwardly as shown by dotted lines in Fig. 4 and to urge the keeperlever l-3 irom its dotted line position to itssolid line position shown in Fig. 4.

.Theside flanges 2, arm 9, and keeper 'lev.er l3, are all substantially dush andtcoplanular. i-The side flanges, however, are ofiset slightly so that they may underlie a panel slotted to accommodate the arm 9 and keeper lever I3. By reason of the fact that the material from which the panel or the like is formed is extremely thin, the amount of offset is correspondingly slight.

The margins A of the panel opening are usually reinforced in order to provide adequate support for the periphery of the panel or the like; consequently, the offset provided in arm 8 is normally greater than that of the side flanges 2. It will be noted that the only portion of the levers comprising the latch assembly which bear against the structure in which the latch is mounted, is the ofiset arm 8 extending under the necessarily reinforced margins of the panel opening. The remaining arm 9 of the latch lever 1 bears against the keeper lever l3 and the oiiset end 14 of the keeper lever bears against the web 3. Without addin appreciable weight, the latch may be constructed of steel or other material more readily adapted than the panel to withstand wear. Furthermore, particularly by reason of the web 3 and its engagement by the keeper lever, the latch as sembly may be latched in its fiush or secured relation before assembling, whereas without the web 3 there would be no means of controlling the keeper lever until installation.

It will also be noted that the journal pins 6 and t2 tie the two side flanges 2 rigidly together and supplement the connection afforded by the web 3. The pin I2 also serves as a stop to limit inward movement of the arm 9 as the latch lever is forced to its closed position.

Operation of the latch assembly is as follows: The latch assembly is unlocked by pressing inwardly on the keeper lever at a point remote from its engagement with the latch lever. The latch assembly is locked by pressing inwardly on the arm 9, causing its cam face H to ride on the adjacent edge of the keeper lever and move the keeper lever toward its dotted line position shown in Fig. 4, until the offset tip 10 of the arm 9 clears the keeper lever, whereupon the keeper lever snaps to its closed position.

Many other embodiments of the invention may be resorted to without departing from the spirit of the invention.

We claim:

1. A flush latch structure, comprising: a mount;

'ing plate including coplanular side flanges connected at one end by an end web and defining a longitudinal slot extending from said web to the other end of said plate, and journal lugs bordering said slot; tandem disposed levers each of channel cross-section, fitting within said slot between said journal lugs, and adapted to occupy coplanular closed positions and angular open positions; and pins journalling said levers extending between said lugs and coacting with said web to space said side flanges; the first of said levers pivoted at one end by its pin and including a lip engageable with said web when said lever is in its closed position; the second of said levers pivoted intermediate its ends to form opposed arms, one arm terminating in a lip adapted to fit under the journalled end of the first lever when said second lever is in its closed position, the other arm of said second lever forming a latching element.

2. A. fiush latch structure, comprising: a mounting plate including coplanular side flanges connected at one end by an end web and defining a longitudinal slot extending from said web to the other end of said plate, and journal lugs bordering said slot; tandem disposed levers each of channel cross-section, fitting Within said slot between said journal lugs, and adapted to occupy coplanular closed positions and angular open po-- sitions; pins journalling said levers extending between said lugs and coacting with said web to space said side flanges; the first of said levers pivoted at one end by its pin and including a lip engageable with said web when said lever is in its closed position; the second of said levers pivoted intermediate its ends to form opposed arms, one arm terminating in a lip adapted to fit under the j'ournalled end of the first lever when said second lever is in its closed position, the other arm of said second lever forming a latching element; and spring means attached at its extremities to said levers and positioned to retain said first lever in its closed position and urge said second lever to its open position.

3. A flush latch structure, comprising: a mounting plate including coplanular side flanges connected at one end b an end web and defining a longitudinal slot, and journal lugs bordering said slot; tandem disposed levers each of channel cross-section, fitting within said slot between said journal lugs, and adapted to occupy coplanular closed positions and angular open positions; and pins journalling said levers extending between said lugs and coacting with said web to space side flanges; the first of said leverspivoted at one end by its pin and including a lip engage-able with said web when said lever is in its closed position; the second of said levers ineluding an offset lip fitting under the fulcrurned end of the first lever when said levers are in closed position; and a cam face at the under side of said end engageable with said first lever to move it into its open position clear of said second lever whereby said second lever may pressed into position, the pin for said first lever being so positioned as to constitute a stop lim-- itin inward travel of said cam face, the other end of said second lever forming a latching ele ment.

4. A iiush latch structure, comprising: a mounting plate including coplanular side flanges connected at one end by end Web and defining a longitudinal slot, and journal lugs bordering said slot; tandem disposed levers each of channel cross-section, fitting within said slot between said journal lugs, and adapted to occupy coplan ular closed positions and angular open positions; and pins journalling said levers extending lie-- tween said lugs and coasting with said web to space said side flanges; the first of said levers pivoted at one end by its pin and including a lip engageable with said web when said lever is in its closed position; the second of said levers including an offset lip fitting under the fulcrumed end of the first lever when said levers are in a closed position; a cam face at the under side of said end engageable with said first lever to move it into its open position clear of said second lever whereby said second lever may be pressed into position, the pin for said first lever being so positioned as to constitute a stop limiting inward travel of said cam face, the other end of said second lever forming a latching element; and spring means attached at its extremities to said levers and positioned to retain said first lever in its closed position and urge said second lever to its open position.

5. A flush latch structure, comprising: a mounting plate including side flanges connected at one end by an end web and defining a longitudinal slot extending from said web to the other extremity of said plate, and journal lugs bordering said slot; journal pins carried by said lugs and bridging said slot; a keeper journalled by one end on one of said pins, and having a lip at its other end fitting under said web, when in its closed position; a latching lever journalled by the other of said pins, one end of said latching lever being folded upon itself to form a cam face at the extremity of its inner side occupying substantially the outer side of said end adapted to fit under the fulcrumed end of said keeper lever when said latching lever is in its closed position, said cam face being engageable with said keeper lever to move said keeper lever clear as said latch is forced to its closed position, the remaining end of said latching lever adapted in its closed position to project laterally from said mounting plate for width of the latching lever, the 10 engagement with a surrounding structure; said flanges and said levers when closed being substantially flush with each other.

THEODORE HERBERT BECK. LESLIE PHILIP GLICK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,337,531 Stockton Dec. 21, 1943 OTHER REFERENCES German publication Flugsport, published NOV. 23, 1939. 

